First of all you'll have to excuse my lack of pictures at some points, specifically with the clip removal for the carpets, I had to work at a few of them and totally forgot to take pictures. Please consult the included instructions in addition to this guide.
Parts were ordered from Subaru Online Parts and it was this item, which includes Subaru part numbers H7010AJ100 (illum kit) and H0070AJ000 (wiring harness).
Start with the a-pillar cover. Easiest method is to take a trim tool and carefully lift from the top edge. Once you can get a few fingers underneath just pull it away from the windshield.
Here is a picture of the clip that you have to reach into and cut. Carefully slide a pair of angled clippers in and cut the black piece on its long end.
Once that clip is removed you can just lift the pillar cover up and out.
With the pillar cover removed you have to CAREFULLY slide a thin screwdriver behind the airbag. It seems dicey but if you're slow and careful it will slide behind. Then pry the attached portion of the clip that you cut off.
Pillar cover removed
Here is the pillar harness as it's connected originally.
Now remove the black trim piece on the passenger side.
Unclip the wire harnesses.
Now thread the new wiring harness ((H0070AJ000) through the various structures of dash.
I skipped a few steps here where you remove the under dash cover and the door sill pieces from the driver and passenger sides. Thankfully the included instructions are pretty clear for this part so it's fairly straight forward.
Now you will roll back the carpet in the passenger footwell
and the driver's footwell
One thing to keep in mind with the driver's footwell. The "plug" underneath the gas pedal screws off. DO NOT PRY IT. You can just unscrew it by hand, it's not in there tight.
Parts were ordered from Subaru Online Parts and it was this item, which includes Subaru part numbers H7010AJ100 (illum kit) and H0070AJ000 (wiring harness).
Start with the a-pillar cover. Easiest method is to take a trim tool and carefully lift from the top edge. Once you can get a few fingers underneath just pull it away from the windshield.

Here is a picture of the clip that you have to reach into and cut. Carefully slide a pair of angled clippers in and cut the black piece on its long end.


Once that clip is removed you can just lift the pillar cover up and out.
With the pillar cover removed you have to CAREFULLY slide a thin screwdriver behind the airbag. It seems dicey but if you're slow and careful it will slide behind. Then pry the attached portion of the clip that you cut off.

Pillar cover removed

Here is the pillar harness as it's connected originally.

Now remove the black trim piece on the passenger side.

Unclip the wire harnesses.

Now thread the new wiring harness ((H0070AJ000) through the various structures of dash.

I skipped a few steps here where you remove the under dash cover and the door sill pieces from the driver and passenger sides. Thankfully the included instructions are pretty clear for this part so it's fairly straight forward.
Now you will roll back the carpet in the passenger footwell

and the driver's footwell

One thing to keep in mind with the driver's footwell. The "plug" underneath the gas pedal screws off. DO NOT PRY IT. You can just unscrew it by hand, it's not in there tight.